1 files changed, 147 insertions, 0 deletions
diff --git a/pkg/atomicbitops/atomic_bitops_common.go b/pkg/atomicbitops/atomic_bitops_common.go
new file mode 100644
index 000000000..b2a943dcb
--- /dev/null
+++ b/pkg/atomicbitops/atomic_bitops_common.go
@@ -0,0 +1,147 @@
+// Copyright 2018 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build !amd64
+
+package atomicbitops
+
+import (
+	"sync/atomic"
+)
+
+// AndUint32 atomically applies bitwise and operation to *addr with val.
+func AndUint32(addr *uint32, val uint32) {
+	for {
+		o := atomic.LoadUint32(addr)
+		n := o & val
+		if atomic.CompareAndSwapUint32(addr, o, n) {
+			break
+		}
+	}
+}
+
+// OrUint32 atomically applies bitwise or operation to *addr with val.
+func OrUint32(addr *uint32, val uint32) {
+	for {
+		o := atomic.LoadUint32(addr)
+		n := o | val
+		if atomic.CompareAndSwapUint32(addr, o, n) {
+			break
+		}
+	}
+}
+
+// XorUint32 atomically applies bitwise xor operation to *addr with val.
+func XorUint32(addr *uint32, val uint32) {
+	for {
+		o := atomic.LoadUint32(addr)
+		n := o ^ val
+		if atomic.CompareAndSwapUint32(addr, o, n) {
+			break
+		}
+	}
+}
+
+// CompareAndSwapUint32 is like sync/atomic.CompareAndSwapUint32, but returns
+// the value previously stored at addr.
+func CompareAndSwapUint32(addr *uint32, old, new uint32) (prev uint32) {
+	for {
+		prev = atomic.LoadUint32(addr)
+		if prev != old {
+			return
+		}
+		if atomic.CompareAndSwapUint32(addr, old, new) {
+			return
+		}
+	}
+}
+
+// AndUint64 atomically applies bitwise and operation to *addr with val.
+func AndUint64(addr *uint64, val uint64) {
+	for {
+		o := atomic.LoadUint64(addr)
+		n := o & val
+		if atomic.CompareAndSwapUint64(addr, o, n) {
+			break
+		}
+	}
+}
+
+// OrUint64 atomically applies bitwise or operation to *addr with val.
+func OrUint64(addr *uint64, val uint64) {
+	for {
+		o := atomic.LoadUint64(addr)
+		n := o | val
+		if atomic.CompareAndSwapUint64(addr, o, n) {
+			break
+		}
+	}
+}
+
+// XorUint64 atomically applies bitwise xor operation to *addr with val.
+func XorUint64(addr *uint64, val uint64) {
+	for {
+		o := atomic.LoadUint64(addr)
+		n := o ^ val
+		if atomic.CompareAndSwapUint64(addr, o, n) {
+			break
+		}
+	}
+}
+
+// CompareAndSwapUint64 is like sync/atomic.CompareAndSwapUint64, but returns
+// the value previously stored at addr.
+func CompareAndSwapUint64(addr *uint64, old, new uint64) (prev uint64) {
+	for {
+		prev = atomic.LoadUint64(addr)
+		if prev != old {
+			return
+		}
+		if atomic.CompareAndSwapUint64(addr, old, new) {
+			return
+		}
+	}
+}
+
+// IncUnlessZeroInt32 increments the value stored at the given address and
+// returns true; unless the value stored in the pointer is zero, in which case
+// it is left unmodified and false is returned.
+func IncUnlessZeroInt32(addr *int32) bool {
+	for {
+		v := atomic.LoadInt32(addr)
+		if v == 0 {
+			return false
+		}
+
+		if atomic.CompareAndSwapInt32(addr, v, v+1) {
+			return true
+		}
+	}
+}
+
+// DecUnlessOneInt32 decrements the value stored at the given address and
+// returns true; unless the value stored in the pointer is 1, in which case it
+// is left unmodified and false is returned.
+func DecUnlessOneInt32(addr *int32) bool {
+	for {
+		v := atomic.LoadInt32(addr)
+		if v == 1 {
+			return false
+		}
+
+		if atomic.CompareAndSwapInt32(addr, v, v-1) {
+			return true
+		}
+	}
+}